The present invention pertains to gemstones and, more particularly, to a unique cut design for a diamond featuring controlled brilliance and dispersion that is immediately and recognizably different from cut designs currently known in the art in that it allows a viewer to readily perceive and appreciate the depth of the diamond material.
Diamond is an extremely hard substance that is created over millions of years in the depths of the earth under extremely harsh conditions. Extremely rare and difficult to secure, diamonds are desirable to consumers because of the unique and attractive distinguishing properties of cut stones including: brilliance, dispersion and scintillation. This combination of optical properties is unique to diamond material and is maximized when a diamond is well cut. The facet arrangement of a cut is essential to controlling the interaction of light that is necessary to display a diamond's beauty.
Brilliance refers to the amount of light passing through the table of the stone that is reflected back to the viewer by facet reflection. Light enters the diamond through the crown, hits one pavilion side, bounces to the opposite pavilion side and then is reflected back through the crown to the viewer. All facets must support the critical angle, optimally 24.5°, in order to achieve this light interaction. Failure to work around the critical angle in the design of the stone will cause light entering the crown to exit the diamond through the pavilion, instead of reflecting through the crown, resulting in a dark and dull stone.
Dispersion, also known as fire, is a measure of the degree to which white light entering the crown of the stone is broken up into spectral colors and returned back to the viewer through the crown. Dispersion is based on the refractive index, a measure of the degree to which light bends as it passes from the air to the stone. Diamond has one of the highest refractive indices for natural, transparent gemstones. Dispersion is influenced by the facet angles which control the manner in which light enters and exits the diamond, the number of internal facets in the stone design and the number of times that light rays spread across the facet junctions of the diamond. These factors directly affect the fire produced by a finished diamond and thus dispersion is also affected by the manner in which a diamond is cut and the angles employed in that cut.
Scintillation, often equated with the sparkle of a diamond, is an indication of the different light patterns obtained when the position of the stone or the observer is moved under light. The best examples of scintillating diamonds are found in round brilliant cuts. They display an eight-pointed star, radiating from the culet of the diamond when viewed from the table. Optimal scintillation displays a pleasing, even pattern of white flashes that results from proper facet symmetry.
Cut, including the facet arrangement, is the human contribution to a diamond's beauty and has important effects on the qualities of brilliance, scintillation and dispersion. Proportions are the key to the attractiveness of the cut. The relationships between the sizes and angles of the various parts and facets must successfully combine the display of brilliance, sparkle and fire—the most important elements of a diamond's visual appeal. Modern diamond cuts are the result of hundreds of years of study and experimentation of how to best display these unique and prized diamond qualities. It is desirable to create new and recognizable cuts of diamond for the discerning diamond buyer as a diamond must stand out as a stylish alternative to the traditional diamond cuts in order to attract the buyer. As a result, several cuts that most effectively optimize desirable diamond qualities of brilliance, dispersion and scintillation have become industry standards. Traditional gemstone cuts may be classified into three general categories: the brilliant cut, the step cut, and the hybrid or mixed cut.
The brilliant cut is traditionally used to create a round cut stone. This cut attempts to achieve maximum brilliancy and dispersion. The brilliant cut crown employs triangular facet patterns that radiate from a large central table facet towards the girdle edge. The pavilion mains radiate from the culet towards the girdle. The numerous facets employed produces maximum brilliance, forcing all light that enters the crown to be refracted and reflected from the pavilion facets back through the crown. Thus, the brilliant cut maximizes the fire of a diamond producing a highly recognizable and marketable stone. Many variations of brilliant cut stones exist in the art.
Step cut is a term of art used to define a rectangular shaped gemstone. Step cut is defined in the The GIA Diamond Dictionary, third edition, 1993, as a cutting style in which long, narrow, four-sided facets are arranged in rows parallel to the girdle on both the crown and the pavilion. There are usually three rows, although this may vary. Emerald cuts and baguettes are examples of step-cut designs.
The step cut is a rectangular or square shaped cut. The step cut crown is formed of three concentric rows of trapezoidal facets cut parallel to the girdle and radiating out from an octagonally shaped table facet having beveled corners. The step cut pavilion has two pairs of opposing pavilion sides and four pavilion corners. The pavilion further has three concentric rows or steps between the girdle and the culet, each step consisting of eight trapezoidal facets cut parallel to the girdle.
The step cut pavilion of the present invention has two pairs of opposing pavilion sides and four pavilion corners. The step cut pavilion of the present invention further has one or more steps consisting of eight facets comprising trapezoidal facets cut parallel to the girdle, which form the rectangular or square pavilion shape, and triangular facets, which form the pavilion corners. The step immediately adjacent to the girdle has triangular facets, which add brilliance to the pavilion when viewed through the crown.
Hybrid or mixed cuts employ a combination of brilliant and step facets, attempting to achieve the classic look of a step cut stone with brilliance and dispersion nearer to that of a brilliant cut stone. Traditional mixed cut gemstones employ a step cut crown combined with a brilliant cut pavilion.
The commercial utility for creative and new diamond cuts has led to the modern cuts such as the highly reflective Princess cut, with its mix of brilliant and step cut facts, the Escada cut, with a star-shaped reflection, the Lucida, with its 50 brightly reflective facets, the Eternal cut with 80 reflective facets and the Ashoka. Most modern cut designs focus on achieving maximum brilliance and dispersion in order to achieve market distinction.
However, these preparations of diamonds while attempting to spread maximum brilliance and fire fail to emphasize the qualities of depth, hardness, and clarity also unique to diamond material. “The name diamond refers to its hardness (Greek—adamas, the unconquerable). There is nothing comparable to it in hardness; it is therefore nearly imperishable.” Schumann, Walter, Gemstones of the World, Sterling Publishing Co., Inc. New York. While it is not desirable to create a stone that completely lacks brilliance; as such a stone resembles a piece of glass and gives no hint as to the special nature of a diamond, no cut in the art achieves a balance between the display of qualities of brilliance, dispersion and fire and the qualities of depth, hardness and clarity. The facet arrangement of the present invention achieves a controlled balance between the optical properties of brilliance, dispersion and scintillation so that one property does not overpower the others thereby providing a controlled brilliance while also providing a view deep into the stone and promoting a sense of the hardness and clarity of the diamond material. The instant invention discloses a new coherent design that takes into consideration optical qualities and critical angles in order to create a unique and valuable stone.